What if that communication was an attempt at discovering the leak source? Maybe there is an uniquely identifiable token or wording in the original mail(s) (per division, or team). Did any one counted the spaces or looked for invisible Unicode characters?
They could also find a few places where synonyms can be substituted without sounding weird, a few places where a comma is optional or can be replaced with a dash, ... much more likely to survive a journalist doing the responsible thing and retyping the e-mail.
For example:
His {stated, claimed} motivation {is, was} that he {wanted a promotion that he did not receive, did not receive a promotion he wanted}. {In light of, Given} {these, his} actions, not promoting him was definitely the right {move, choice}.
This can be detected by people comparing two e-mails, but the unicode trick can often be found just by looking at one of them, so I wouldn't say one is more stealthy than the other.
